Effect of NaBH4 concentration on the characteristics of PtRu/C catalyst for the anode of DMFC prepared by the impregnation method

• DOI: 10.1016/j.cattod.2007.12.034
• Publication Date: 2008-01-27T01:40:25Z
• Authors: Min-Soo Hyun; Sang-Kyung Kim; Byungrock Lee; Donghyun Peck; Yonggun Shul; Doohwan Jung
• Keywords: Linear sweep voltammetry

Abstract PtRu/C catalysts were prepared using an aqueous co-impregnation method with NaBH 4 as a reducing agent. In order to investigate the effect of the reducing agent concentration, metal ions were reduced in different NaBH 4 concentrations for which the molar ratios of NaBH 4 to metal ions were controlled to 1, 2, 5, 15, 50, and 250. The electrochemical properties were studied by cyclic voltammetry in a 0.5 M H 2 SO 4 solution. The surface compositions and oxidation states of the catalysts were observed by X-ray photoelectron spectroscopy (XPS). According to the X-ray diffraction (XRD) results, Pt (fcc) peak shifts were observed and crystal sizes were calculated. The electro-catalytic activities of the prepared catalysts for methanol electro-oxidation were estimated using linear sweep voltammetry. Unit cell tests were carried out to compare the direct methanol fuel cell performances. The NaBH 4 concentration was found to affect the dispersion and the surface composition of the prepared PtRu particles. Optimum molar ratios of NaBH 4 to metal ions were 5 and 15 for methanol electro-oxidation.